Composite, method for producing a product from a composite, and method for producing a shaped body from a composite

ABSTRACT

The invention relates to a composite for producing shaped bodies, which comprises at least one binding agent, at least one filler and at least one reinforcing agent. The invention is characterized in that the at least one filler and the at least one reinforcing agent are comminuted bast fiber plants and/or whole bast fiber plants. The invention also relates to a method for producing a product, especially a granulate, from a composite, which involves the following method steps: coating an extruder with at least on binding agent and bast fiber plants and/or comminuted bast fiber plants; melting at least one binding agent; extruding the material; granulating the extruded material, and; solidifying the material after cooling. The invention additionally relates to a method for producing a shaped body from a composite, which involves the following method steps: feeding a granulate made of the composite into an injection molding machine; melting the granulate; injecting the molten material, especially under pressure, and; solidifying the composite in the mold by cooling. The invention relates to another method for producing a shaped body from a composite, which is characterized by the following steps: feeding a mixture consisting of at least one binding agent and of bast fiber plants and/or of comminuted bast fiber plants, especially in their natural composition, into an extruding machine or into a strand depositing device, and; extruding or strand-depositing the mixture, whereby the mixture is at least partially melted.

[0001] The invention relates to a composite for producing shaped bodies,said composite comprising at least one binding agent, at least onefiller and at least one reinforcing agent. The invention furthermorerelates to a method for producing a product from a composite, as well asa method for producing a shaped body from a corresponding composite.

[0002] Raw-material suppliers frequently conduct costly andtime-intensive research and development to meet the increasing demandsfor technologically high quality shaped parts of thermoplastic moldingmasses. The development is aimed at obtaining ever more complicatedmolecular structures, for example to achieve even higher form stabilityunder heat or even better cold impact resistance of the materials or tofurther improve the durability. A large share of the research anddevelopment money is furthermore used to develop synthetically producedglass, coal or aramide fibers with a so-called sizing material, meaninga bonding agent between the reinforcing fiber and the polymer matrix.This is designed to obtain plastic composites or composite materialswith increased strength. The aforementioned developments are becomingmore and more detailed and complex, thus making the plastic materialsmore and more expensive.

[0003] At present, plastic materials for high-quality applications areeither polymerized in a synthetically involved technique or up to 40%glass, coal or aramide fibers are mixed into a low-quality polymermatrix as reinforcement. A high amount of energy is required to producesuch fibers. In addition, already macerated natural fibers such as flaxor sisal are presently worked into synthetic material matrices to createa substitute for glass fibers. However, no replacement has been found sofar for glass fibers with respect to strength.

[0004] Starting with this state of the technology, it is the object ofthe present invention to provide a composite for producing a productmade from this composite, to provide a method for producing shapedbodies as well as to provide corresponding techniques for producingthese shaped bodies at low cost and using the lowest possible amount ofsynthetic products on the basis of crude oil. In particular, it is theobject of this invention to contribute to a reduction in CO₂ emissions.

[0005] It is furthermore an object of the present invention to makeavailable a technologically high-quality composite for producing shapedbodies. Furthermore, it should be possible to produce these shapedbodies without expensive synthetic fiber production techniques, as wellas at cheaply and with a low amount of energy.

[0006] This object is solved with a composite for producing shapedbodies, which contains at least one binding agent, at least one filler,and at least one reinforcing agent. The composite is modified in thatthe at least one filler and the at least one reinforcing agent arecomminuted bast fiber plants and/or whole bast fiber plants.

[0007] As a result of this modification according to the invention ofstandard composite materials, it is possible to obtain technologicallyhigh-quality composites since bast fiber plants have an extremely hightensile strength and thus are particularly easy to use intechnologically high-quality composite polymers. In addition, it ispossible to produce corresponding composites or composite materials inthis way, which are based to a large extent or completely on renewablecrude materials, thus making them CO₂ neutral. Owing to the fact that nopolymerization technology is required and the expensive and involvedsynthetic fiber production is omitted, composite materials of this typeand shaped bodies produced from these materials can be produced atconsiderably lower cost and require noticeably lower energy amounts forthe production.

[0008] Within the framework of this invention, the term “composite” inparticular also comprises the term “composite material.”

[0009] Particularly preferred as filler and reinforcing agent arecomminuted bast fiber plants, which for the most part are not maceratedbut only cut up. A preferred composite in particular is modified in thatthe bast fiber plants and/or the comminuted bast fiber plants areessentially present in the natural composition of the plant components.Normally, the plant components (wood, fibers) are present as a unit,separated, macerated or still in part adhering to each other. Whencutting up the bast fiber plants, a partial or complete separationbetween wood (shives¹) and fibers can occur, which indeed can also haveadvantages.

[0010] The term shives in this connection refers to parts of thecomminuted, lignified inside portion of the plant stem.

[0011] It is particularly preferred if the comminuted bast fiber plantscomprise few shives that are separated and/or partially separated fromthe bast fibers. A natural composition of the plant components, inparticular, is understood to mean that these still exist in the samequantitative composition as in nature.

[0012] The bast fiber plants and/or the comminuted bast fiber plants arepreferably dried. The bast fiber plants and/or the comminuted bast fiberplants are furthermore preferably hemp, flax, kenaf, stinging nettleand/or toad flax. The dried and comminuted and/or cut bast fiber plants,preferably used as filler and reinforcing agents, have a considerablyhigher tensile strength than other natural fibers in the naturalcomposition of the plant components and are thus predestined for use intechnologically high-quality composite polymers. The fiber portion inthis case functions as reinforcing agent and the shive portionessentially as the filler. Using the plant components in their naturalcomposition means that the relatively involved separating and subsequentfeeding operations following the comminuting or at least partial breakupof the material can be omitted.

[0013] Technologically high-quality composite materials can be obtainedif the binding agent preferably includes synthetic and/or nativemonomers and/or polymers. The term native within the framework of thisinvention in particular also means biogenic. A native and/or biogenicmonomer is lactic acid, for example, a breakdown product of thefermentation process. Native and/or biogenic polymers, for example,include plant starches from the family of polysaccharides, as well aslignin or even keratin from the family of animal proteins. However, thebiogenic and/or native polymers or monomers can also include other knownmaterials. Synthetic polymers, for example, are polyethylene,polypropylene, polystyrene and other polymers. The polymers arepreferably thermoplastic and function as plastic matrix. The syntheticpolymers are preferably produced from petrochemical base materials.

[0014] Additives are preferably provided and include, for example,bonding agents between the at least one filler and the at least onereinforcing agent and the matrix and/or the binding agent. Particularlysuitable are additives that reduce, in particular, the combustibilityand breakdown ability of the bast fiber plants and/or the comminutedbast fiber plants and/or the composites. For the purpose of thisinvention, a binding agent in particular also refers to a matrix.

[0015] It is particularly preferable if the reinforcing agents and thefillers are essentially enclosed completely by the binding agents andare fixated at their location.

[0016] It is preferable if the at least one filler and the at least onereinforcing agent are essentially combined, in particular in the naturalform, thus making it possible to realize an especially cost-effectivecomposite.

[0017] In addition, the composite can be foamed up if it contains atleast one expanding agent, e.g. for producing insulating materials. Theeffect of the expanding agent preferably is either chemical and/orphysical. A preferred example of a chemically effective expanding agentis a foam-producing material or, for example, sodium bicarbonate (bakingpowder). A physically effective expanding agent, for example, is wateror CO₂.

[0018] The production of the respective composites and thus also therespective shaped bodies is particularly easy if the at least one fillerand/or the at least one reinforcing agent preferably functions ascarrier for at least one expanding agent and/or at least one foamingagent. Water that is already present in the plants and/or plant parts oris additionally added and causes a foaming of the matrix and/or thebinding agent at processing temperatures above 100° C. is particularlysuitable for this. Insulation materials can thus be produced easily andcheaply while using safe expanding agents. The moisture content of theplant parts can vary, for example between 3% and 40% for hemp. Followinga normal drying process, the plant parts generally contain approximately12% residual moisture.

[0019] The aforementioned plants and plant parts furthermore have theadvantage of causing low wear on the respective production machines ascompared to the use of synthetic fibers, thus extending the service lifeof compounding and production machines. In addition, the processing ofnatural fibers does not pose a health threat, in contrast to theprocessing of glass fibers, so that fewer protective measures arerequired.

[0020] The composite is preferably produced by means of extrusion,injection-molding and/or strand-depositing.

[0021] A method for producing a product, in particular a granulate, froman aforementioned composite preferably includes the following steps:

[0022] supplying an extruder with at least one binding agent and bastfiber plants and/or comminuted bast fiber plants;

[0023] melting down of at least one binding agent;

[0024] extruding of the material;

[0025] granulating of the extruded material; and

[0026] solidification of the composite material through cooling.

[0027] The granulating can also be realized after the completesolidification of the material by cutting the extruded product.

[0028] For producing shaped bodies from the granulated and extrudedmaterial, the material is processed further with the following steps:

[0029] feeding of the granulate into an injection-molding machine;

[0030] injecting the melted material into a mold, in particular underhigh pressure;

[0031] solidification through cooling of the composite inside the mold.

[0032] As a result of this preferred injection-molding process, it iseasy to produce in particular shaped bodies from the aforementionedcomposites, wherein comminuted bast fiber plants in particular are used.

[0033] While the bast fiber plants or the comminuted bast fiber plantsare added or following this process, they are preferably stirred and/ormixed into the melted binding agent. The bast fiber plants and/or thecomminuted bast fiber plants are preferably added before the at leastone binding agent is melted. It is preferable if the comminuted bastfiber plants are comminuted in such a way that pieces measuring up to 3mm result.

[0034] The mixture consisting of at least one binding agent and the bastfiber plants and/or the comminuted bast fiber plants is preferablyheated up, such that at least one expanding agent is triggered toexpand. As a result of this preferred exemplary embodiment, the mixtureand in particular the binding agent foams up. An insulating material,for example, can thus be produced easily with this measure. Aparticularly easy and cheap method of foaming up is provided if thetemperature is preferably at 100° C. or higher and the expanding agentis water, which is present in the bast fiber plants or the comminutedbast fiber plants and/or in the filler and/or the reinforcing agent orwhich is added.

[0035] The bast fiber plants and/or the comminuted bast fiber plants arepreferably dried before they are added and/or supplied to the bindingagent. The bast fiber plants and/or the comminuted bast fiber plants arefurthermore enriched with water and/or another expanding agent beforebeing added to the binding agent. An expanding agent can additionally oralternatively be added to the binding agent before or after thecomminuted bast fiber plants are added. As a result of this measureaccording to the invention, the foaming effect can be increased.

[0036] An additional method for producing a shaped body from acomposite, of the type described in the above, preferably comprises thefollowing steps:

[0037] supplying a mixture comprising at least one binding agent andbast fiber plants and/or comminuted bast fiber plants, in particular intheir natural composition, to an extruder or a strand-depositing device;and

[0038] extruding or strand-depositing the mixture, wherein the mixtureis at least partially melted down.

[0039] Large slabs or semi-finished products can, for example, beproduced with this preferred method. Insulating materials and soundinsulating and/or heat-insulating shaped bodies can be produced easilyif the mixture preferably is heated up enough, so that at least oneexpanding agent is triggered to expand. The temperature preferably is at100° C. or higher and the expanding agent preferably is water that ispresent in the bast fiber plants or the comminuted bast fiber plants orin the filler and/or the reinforcing agent, or which is added.

[0040] The bast fiber plants and/or the comminuted bast fiber plants arepreferably dried prior to being mixed into the at least one bindingagent. The bast fiber plants and/or the comminuted bast fiber plants arefurthermore enriched with water and/or at least one additional expandingagent before being mixed into the binding agent. In addition to oralternatively, an expanding agent can be added to the binding agentbefore or after the addition of the comminuted bast fiber plants. Thefoaming effect can be increased as a result of this measure according tothe invention. Thus, a higher foaming effect can be achieved with thispreferred embodiment of the method.

[0041] A shaped body preferably consists at least in part of a compositeof the type described in the above and/or is preferably producedaccording to one of the above-described methods. Long bast fiber plantsections have an advantage with shaped bodies in the form of slabs.Thermoplastics filled with bast fiber plants, for example in the form ofslab goods or semi-finished products, can be used for producingwindowsills or similar items. Shaped bodies of this type show hardly anyswelling caused by the effects of water. Shaped bodies that can beproduced include, for example, wall reinforcements, floor stabilizersand slope stabilizers, floor plates with raised areas having non-skidtop surfaces and provided, for example, with an anchor at the bottom aswell as posts, meadow fences or garden fences, planters, poles forgrowing plants, manhole and pipe covers, outer shells for waste baskets,feed troughs, leakage basins, dog houses, raised seats, log-type playhouses, climbing towers, garden furniture, park benches and the like. Inaddition, corresponding shaped bodies are also suitable for use asviewing and noise protection walls.

[0042] It is particularly preferable if recycled materials are used forthe binding agents. The correspondingly produced shaped bodies can beused in road construction and as structural components for securing theslope and embankment area. As previously indicated, they can function asinsulating materials or as large-dimension injection-molded articles,for example surfboards, boogie boards or similar items.

[0043] A device disclosed in WO 00/14312, in particular, can be used forcomminuting the fiber plants. However, the fiber plant material is notcompressed or broken up with this method, but is only cut to the desiredlength. For this, the fiber plant material is transferred to a receivingchute, meaning a receiving chute of a tobacco cutter known in thetobacco-processing industry, and is conveyed to an orifice. There, it iscut into sections having a desired length with the aid of a cuttingdevice, provided with rotating or linearly moving blades. Within theframework of said invention, the fiber components as well as the woodand shive components preferably are not further processed and separated.

[0044] Bast fiber plant sections measuring from 0.1 to 150 mm, inparticular from 2 mm to 50 mm, are preferably provided. With thepreferred injection-molding process, fiber sections of 2 mm are used,wherein the share of fibers used can reach up to 40%.

[0045] With a preferably realized strand-depositing method, a fibershare of up to 70% can be realized.

[0046] Preferred matrix materials and/or binding materials used arepolyethylene with a high density (PE-HD), polypropylene homopolymer(PP), polystyrene (PS) and starch (MaterBi², Y-type³).

1. A composite for producing shaped bodies, comprising at least onebinding agent, at least one filler and at least one reinforcing agent,characterized in that the at least one filler and the at least onereinforcing agent are comminuted bast fiber plants and/or whole bastfiber plants.
 2. The composite according to claim 1, characterized inthat the comminuted bast fiber plants and/or the whole bast fiber plantsare present in the natural composition of the plant components.
 3. Thecomposite according to claim 1 and/or 2, characterized in that the bastfiber plants and/or the comminuted bast fiber plants are dried.
 4. Thecomposite according to one or several of the claims 1 to 3,characterized in that the bast fiber plants and/or the comminuted bastfiber plants are hemp, flax, jute, kenaf, stinging nettles and/or toadflax.
 5. The composite according to one or several of the claims 1 to 4,characterized in that the binding agent comprises synthetic and/ornative monomers and/or polymers.
 6. The composite according to one orseveral of the claims 1 to 5, characterized in that the at least onefiller and the at least one reinforcing agent, in particular in thenatural form, are essentially combined.
 7. The composite according toone or several of the claims 1 to 6, characterized in that the compositeadditionally contains at least one expanding agent.
 8. The compositeaccording to claim 7, characterized in that the effect of the expandingagent is chemical and/or physical.
 9. The composite according to claim 7and/or 8, characterized in that the at least one filler and/or the atleast one reinforcing agent functions as carrier for at least oneexpanding agent.
 10. The composite according to one or several of theclaims 1 to 9, characterized in that the composite can be produced withthe aid of extrusion, injection-molding and/or strand-depositing.
 11. Amethod for producing a product, in particular a granulate, from acomposite according to one or several of the claims 1 to 10,characterized by at least the following steps: coating of an extruderwith at least one binding agent and bast fiber plants and/or comminutedbast fiber plants; melting of at least one binding agent; extruding ofthe material; granulating of the extruded material; and solidificationof the material through cooling.
 12. The method according to claim 11,characterized in that the material can be granulated before as well asafter the solidification of the composite.
 13. A method for producing ashaped body from a composite according to one or several of the claims 1to 10, characterized by at least the following steps: feeding agranulate of the composite material into an injection-molding machine;melting of the granulate; injection-molding of the melted material, inparticular under high pressure; and solidification of the compositeinside the mold through cooling.
 14. The method according to claim 13,characterized in that the granulate is produced according to one or bothof the claims 11 and
 12. 15. The method according to one or both of theclaims 11 or 12, characterized in that during the process of adding thebast fiber plants and/or the comminuted bast fiber plants or thereafter,these are stirred and/or mixed into the melted binding agent.
 16. Themethod according to one or several of the claims 11, 12 and 15,characterized in that the bast fiber plants and/or the comminuted bastfiber plants are added prior to the melting of the at least one bindingagent.
 17. The method according to one or several of the claims 11, 12,15 and 16, characterized in that the comminuted bast fiber plants arecomminuted so as to result in sections measuring from 0.1 to 150 mm andin particular from 2 to 50 mm.
 18. The method according to one orseveral of the claims 11, 12, 15 to 17, characterized in that themixture consisting of the at least one binding agent and the bast fiberplants and/or the comminuted bast fiber plants is heated up, such thatat least one expanding agent is triggered to expand.
 19. The methodaccording to claim 18, characterized in that the temperature is 100° C.or higher and that the expanding agent is water, which is present in thebast fiber plants and/or the comminuted bast fiber plants and/or in anadditional filler and/or an additional reinforcing agent, or which isadded.
 20. The method according to one or several of the claims 11, 12,15 to 19, characterized in that the bast fiber plants and/or thecomminuted bast fiber plants are dried before being added to the bindingagent.
 21. The method according to one or several of the claims 11, 12,15 to 20, characterized in that the bast fiber plants and/or thecomminuted bast fiber plants are enriched with water and/or at least oneother expanding agent prior to being added to the binding agent.
 22. Themethod for producing a shaped body from a composite according to one orseveral of the claims 1 to 10, characterized by the following steps:supplying a mixture, consisting of at least one binding agent and bastfiber plants and/or comminuted bast fiber plants, in particular in theirnatural composition, to an extruder or a strand-depositing device; andextruding or strand-depositing the mixture, wherein the mixture is atleast partially melted.
 23. The method according to claim 22,characterized in that the mixture is heated up enough, so that at leastone expanding agent is triggered to expand.
 24. The method according toclaim 23, characterized in that the temperature is 100° C. or higher andthat the expanding agent is water, which is present in the bast fiberplants and/or the comminuted bast fiber plants and/or in an additionalfiller and/or an additional reinforcing agent, or which is added. 25.The method according to one or several of the claims 22 to 24,characterized in that the bast fiber plants and/or the comminuted bastfiber plants are dried before being mixed with the at least one bindingagent.
 26. The method according to one or several of the claims 22 to25, characterized in that the bast fiber plants and/or the comminutedbast fiber plants are enriched with water and/or at least one additionalexpanding agent before being mixed with the binding agent.
 27. Theshaped body, at least partially consisting of a composite, according toone or several of the claims 1 to 10 and/or produced according to amethod as defined in one or several of the claims 13 and/or 14 and/oraccording to one or several of the claims 15 to 27.